This invention relates generally to writing instruments and, more particularly, to a writing instrument which may be conveniently converted from a compact storage configuration to a lengthened writing configuration. More particularly, a writing portion may be selectively stored within a case or attached thereto for use in writing.
Various devices have been proposed in the art for providing compact writing instruments that are convertible from a storage configuration to a writing configuration, such as the device disclosed in U.S. Pat. No. 4,974,982. In addition, devices have been proposed for advancing or retracting a writing element by rotation of the writing instrument housings. Although assumably effective for their intended purposes, these devices do not provide the ability to threadably attach or detach a writing element from a case without consequently rotatably advancing or retracting the writing element itself.
Therefore, it is desirable to have a writing instrument which is selectively threadably held in a storage configuration within a tubular housing or threadably attached to the housing in a writing configuration. Further, it is desirable to have a writing instrument in which a writing element may be advanced or retracted without disrupting the threaded relationship between the writing portion and housing portion.